Quoting from Log Viewer results significantly delayed - #2 by kazurayam
the “Log Viewer” gets significantly delayed in relation to the actions being performed on the website
This may occur when you have too many messages from the executed Test Case, eg. by WebUI.comment(msg) or by “Step Execution Log”. …
You have an alternative way of decreasing Test Cases’ “Step Execution Log” messages.
Katalon Studio would not emit any verbose “Step Execution Log” messages for Keywords. I recommend you to transfer your codes in the Test Cases (Groovy scripts) into the Keywords (Groovy classes). Especially you should transform the codes which are repeatedly executed. Once you have implemented it as Groovy classes, you will replace the original codes in Test Cases with codes that invoke methods of the new Classes. Then the amount of “Step Execution Log” will become less. Less messages will make Log Viewer responsive.